Silicon carbide (SiC) is a wide-band gap semiconductor that exceeds other semiconducting materials (except diamond) in electrical, mechanical, chemical, and radiation stability. In this paper, we report a novel approach to fabrication of SiC nano films on a Si substrate, which is based on the endotaxial growth of a SiC crystalline phase in a graphite-like carbon (GLC) matrix. GLC films were formed by carbonization of rigid rod polyimide (PI) Langmuir-Blodgett (LB) films on a Si substrate at 1000 degrees C in vacuum. After rapid thermal annealing of GLC films at 1100 degrees C and 1200 degrees C, new types of heterostructures SiC(10 nm)/GLC(20 nm)/Si(111) and SiC(20 nm)/GLC(15 nm)/SiC(10 nm)/Si(111) were obtained. The SiC top layer was formed due to the Si-containing gas phase present above the surface of GLC film. An advantage of the proposed method of endotaxy is that the SiC crystalline phase is formed within the volume of the GLC film of a thickness predetermined by using PI LB films with different numbers of monolayers for carbonization. This approach allows growing SiC layers close to the 2D state, which is promising for optoelectronics, photovoltaics, spintronics.

For the first time, multilayer graphene films on quartz glass were obtained by carbonization of the Langmuir-Blodgett films of polyimide. On the Raman spectra of the carbonized polyimide films, the G, D bands and a wide band in the region of 2300–3200 cm-1 were observed. Using the method of transmission microscopy, it was shown that films consist of “stacks” of layers with a interlayers distance of 0.36 nm. The surface resistance of films 5 nm thick was 1.2±0.2 kOmega, and the transmittance was 87% at lambda=550 nm. In the infrared region of the spectrum, the transmittance was 97%, and in the UV region 70-80%.

Multigraphene films have been for the first time obtained on the surface of quartz glass via carbonization of polyimide Langmuir–Blodgett films. The Raman spectra of the films show bands G and D and a broad band at 2300–3200 cm –1 , which are characteristic of graphite-like films. The transmission electron microscopy demonstrated that the films are constituted by “stacks” of layers spaced by 0.36 nm. The surface resistance of the 5-nm-thick films was 1.2 ± 0.2 kΩ, and the transmittance was 87% at λ = 550 nm. The transmittance was 97% in the IR part of the spectrum and 70–80% in the UV part.

High quality single crystal SiC films were prepared by carbonization of polyimide Langmuir-Blodgett films on Si substrate. The films formed after annealing of the polyimide films at 1000°C, 1100°C, 1200°C were studied by Fourier transform-infrared (FTIR) spectroscopy, X-ray diffraction (XRD), Raman spectroscopy, transmission electon microscopy (TEM), transmission electron diffraction (TED), and scanning electron microscopy (SEM). XRD study and HRTEM cross-section revealed that the crystalline SiC film begins to grow on Si (111) substrate at 1000°C. According to the HRTEM cross-section image five planes in 3C-SiC (111) film are aligned with four Si(111) planes at the SiC/Si interface. It was shown the SiC films (35 nm) grown on Si(111) at 1200°C have mainly cubic 3C-SiC structure with a little presence of hexagonal polytypes. Only 3C-SiC films (30 nm) were formed on Si (100) substrate at the same temperature. It was shown the SiC films (30-35 nm) are able to cover the voids in Si substrate with size up to 10 μm.

High-quality crystalline nano-thin SiC films on Si substrates were prepared by carbonization of polyimide (PI) Langmuir–Blodgett (LB) films. The obtained films were characterized by Fourier transform-infrared (FTIR) spectroscopy, X-ray diffraction (XRD) analysis, Raman spectroscopy, transmission electon microscopy (TEM), transmission electron diffraction (TED), and scanning electron microscopy (SEM). We demonstrated that the carbonization of a PI film on a Si substrate at 1000 °C leads to the formation of a carbon film and SiC nanocrystals on the Si substrate. It was found that five planes in the 3C-SiC(111) film are aligned with four Si(111) planes. As a result of repeated annealing of PI films containing 121 layers at 1200 °C crystalline SiC films were formed on the Si substrate. It was shown that the SiC films (35 nm) grown on Si(111) at 1200 °C have a mainly cubic 3C-SiC structure with small amount of hexagonal polytypes. Only 3C-SiC films (30 nm) were formed on the Si(100) substrate at the same temperature. It was shown that the SiC films (30–35 nm) can cover the voids with size up to 10 µm in the Si substrate. The current–voltage (I–V) characteristics of the n-Si/n-SiC heterostructure were obtained by conductive atomic force microscopy.

Continuous decrease of the feature size of transistors in modern integrated circuits (ICs) constrains thickness of auxiliary dielectric layers in interconnects because of their relatively high dielectric constant, which reduces the efficiency of low-k material integration. Dielectric materials used today as barrier or etch-stop layers are usually SiN (k ∼ 7.0) and SiCN (k ∼ 4.8), which k-value significantly exceeds that of recent ultra low-k materials (k < 2.2). In our work we have investigated thin films of rigid-chain polyimide (PI) with a k-value of about 3.2-3.3. This film was deposited using a Langmuir-Blodgett (LB) technique and can be as thin as several monolayers. The intermolecular interaction of densely packed precursor macromolecules within a monolayer formed at the water-air interface makes it possible to avoid penetration of precursor material inside the pores. The latter peculiarity of the deposition process results in a pore sealing effect using a 4 nm PI film.

The Langmuir monolayers and Langmuir-Blodgett films of a comb-like polyimide prepolymer (the rigid-chain polyamic acid alkylamine salt bearing multichains of tertiary amine) were studied. The supramolecular structures of the monolayers and Langmuir-Blodgett films of polyamic acid salts were characterized and a way for the surpamolecular structure to form was proposed based on an analysis of the surface pressure-area isotherms of monolayers on the water surface, investigations of the conditions of monolayer deposition onto solid substrates, and studies of the structures and surface morphology of Langmuir-Blodgett films.

The surface structure of a three-layer Langmuir-Blodgett film of comblike rigid-chain polyimide prepolymer (polyamic acid alkylammonium salt) has been studied by atomic force microscopy (AFM). The AFM data reveal the presence of supramolecular formations consisting of two-dimensional domains in which aliphatic chains of the prepolymer macromolecules are oriented perpendicularly to the substrate. A mechanism responsible for the supramolecular structure formation in the film is proposed.

Atomic-force microscopy, reflectometry, and ellipsometry were applied to analysis of ultrathin films (3.3–13.6 nm) of a rigid-chain polyimide, formed on the surface of a silicon substrate by thermal imidization of Langmuir-Blodgett films of polyamido acid derived from 3,3′,4,4′-diphenyltetracarboxylic acid and ortho-tolidine.

An ultrathin polyimide membrane network has been formed for the first time on a metal grid matrix using the Langmuir-Blodgett method. The ratio of the membrane thickness to the grid mesh reaches 1: 1000.

Langmuir and Langmuir-Blodgett films were first prepared from fullerene C-60 With grafted poly styrene and poly(ethylene oxide). For comparison, Langmuir films were prepared from a pure fullerene C-60 under analogous conditions. For C-60 with grafted polystyrene chains, Langmuir films were best applied on hydrophobic silicon substrates by the Langmuir-Schaefer method; optical microscopic observations showed that the : films are nonuniform in thickness and are composed of aggregates with dimensions less than or equal to 6 mu m. Langmuir films made of C-60 with grafted poly(ethylene oxide) chains were transferred well on hydrophobic and hydrophilic silicon substrates by the Langmuir-Blodgett method; even when the film thickness achieved 10 and 20 layers, the resulting films were as a rule uniform, as detected by optical microscopy.

Langmuir-Blodgett films made from C60 fullerene with grafted polymer chains —polystyrene and polyethylene oxide — are obtained for the first time. The Langmuir-Blodgett films are obtained by the transfer of Langmuir films onto substrates of single-crystal silicon. The Langmuir films and the single-layer Langmuir-Blodgett films of C60 with grafted polystyrene are nonuniform over their thickness and form a network consisting of aggregates with a size of ≤6 μm. The Langmuir films of C60 with grafted polyethylene oxide are much more uniform. They can easily be used to obtain Langmuir-Blodgett films containing up to 20 layers and having a surface that appears smooth under an optical microscope.